lantz
f0c726a42f
This helps with virtualenv although it can open up another security hole if you end up using an unexpected python interpreter. Overall it seems to make sense to err on the side of usability but it's good to be aware of security. However, for the remaining utility scripts that require python 2, we explicitly note this with #!/usr/bin/python2.
128 lines
3.9 KiB
Python
Executable File
128 lines
3.9 KiB
Python
Executable File
#!/usr/bin/env python
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"""
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Test bandwidth (using iperf) on linear networks of varying size,
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using both kernel and user datapaths.
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We construct a network of N hosts and N-1 switches, connected as follows:
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h1 <-> s1 <-> s2 .. sN-1
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h2 h3 hN
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WARNING: by default, the reference controller only supports 16
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switches, so this test WILL NOT WORK unless you have recompiled
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your controller to support 100 switches (or more.)
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In addition to testing the bandwidth across varying numbers
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of switches, this example demonstrates:
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- creating a custom topology, LinearTestTopo
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- using the ping() and iperf() tests from Mininet()
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- testing both the kernel and user switches
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"""
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import sys
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from functools import partial
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from mininet.net import Mininet
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from mininet.node import UserSwitch, OVSKernelSwitch, Controller
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from mininet.topo import Topo
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from mininet.log import lg, info
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from mininet.util import irange, quietRun
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from mininet.link import TCLink
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flush = sys.stdout.flush
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class LinearTestTopo( Topo ):
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"Topology for a string of N hosts and N-1 switches."
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# pylint: disable=arguments-differ
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def build( self, N, **params ):
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# Create switches and hosts
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hosts = [ self.addHost( 'h%s' % h )
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for h in irange( 1, N ) ]
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switches = [ self.addSwitch( 's%s' % s )
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for s in irange( 1, N - 1 ) ]
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# Wire up switches
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last = None
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for switch in switches:
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if last:
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self.addLink( last, switch )
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last = switch
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# Wire up hosts
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self.addLink( hosts[ 0 ], switches[ 0 ] )
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for host, switch in zip( hosts[ 1: ], switches ):
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self.addLink( host, switch )
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def linearBandwidthTest( lengths ):
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"Check bandwidth at various lengths along a switch chain."
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results = {}
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switchCount = max( lengths )
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hostCount = switchCount + 1
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switches = { 'reference user': UserSwitch,
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'Open vSwitch kernel': OVSKernelSwitch }
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# UserSwitch is horribly slow with recent kernels.
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# We can reinstate it once its performance is fixed
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del switches[ 'reference user' ]
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topo = LinearTestTopo( hostCount )
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# Select TCP Reno
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output = quietRun( 'sysctl -w net.ipv4.tcp_congestion_control=reno' )
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assert 'reno' in output
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for datapath in switches:
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info( "*** testing", datapath, "datapath\n" )
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Switch = switches[ datapath ]
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results[ datapath ] = []
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link = partial( TCLink, delay='30ms', bw=100 )
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net = Mininet( topo=topo, switch=Switch,
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controller=Controller, link=link,
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waitConnected=True )
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net.start()
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info( "*** testing basic connectivity\n" )
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for n in lengths:
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net.ping( [ net.hosts[ 0 ], net.hosts[ n ] ] )
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info( "*** testing bandwidth\n" )
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for n in lengths:
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src, dst = net.hosts[ 0 ], net.hosts[ n ]
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# Try to prime the pump to reduce PACKET_INs during test
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# since the reference controller is reactive
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src.cmd( 'telnet', dst.IP(), '5001' )
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info( "testing", src.name, "<->", dst.name, '\n' )
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# serverbw = received; _clientbw = buffered
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serverbw, _clientbw = net.iperf( [ src, dst ], seconds=5 )
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info( serverbw, '\n' )
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flush()
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results[ datapath ] += [ ( n, serverbw ) ]
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net.stop()
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for datapath in switches:
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info( "\n*** Linear network results for", datapath, "datapath:\n" )
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result = results[ datapath ]
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info( "SwitchCount\tiperf Results\n" )
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for switchCount, serverbw in result:
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info( switchCount, '\t\t' )
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info( serverbw, '\n' )
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info( '\n')
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info( '\n' )
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if __name__ == '__main__':
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lg.setLogLevel( 'info' )
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sizes = [ 1, 2, 3, 4 ]
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info( "*** Running linearBandwidthTest", sizes, '\n' )
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linearBandwidthTest( sizes )
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